Guidelines for the Use of Truck-Mounted Attenuators in Work Zones

Truck-mounted attenuator (TMA) usage varies for a number of reasons, including apathy, loss of efficiency (real or perceived), fiscal constraints, and lack of information on when and how to use the devices. Although some individual states have adopted policies, there has not been any coordinated effort to develop guidelines for the use of TMAs on a national basis. A literature review was conducted to determine the extent to which guidelines might have been developed but not widely shared. Five states were visited to solicit information regarding support for, and extent of use of, TMAs. There was a wide range in the number of TMAs presently in use. There was more consistency on other issues including the following: (a) initial support for the use of TMAs came principally from administrators; (b) field support is generally good in states using tilt-up versions of the TMA; (c) reported uses included maintenance activities, construction activities, and emergency incident management (use of TMAs on shadow vehicles was, by policy, the most common application); and (d) there seemed to be little factual basis for the existing application policies. A set of recommended guidelines was developed that included priorities for the deployment of shadow vehicles and TMAs. Two limitations on the significance and suggested use of the guidelines are acknowledged. First, the project did not involve collection and analysis of numerical data. Rather, it represented an effort at bringing together appropriate policies and procedures. Second, the guidelines are more appropriately used as a policy formation and budgeting tool.